Wow, this is quite a remarkable goal set today by the ESA (European Space Agency). They launched the AMAZE project today and wish to print an entire space satellite via a 3D Printer, which requires no screwing, bolting, or nailing. Basically the satellite would be one connected piece. If they can manage this it will save at least 50% their costs, equating to several billion euro.

More Details:
http://rt.com/news/3d-print-satellite-metal-esa-232/